1. Field of the Invention
The present invention relates to a semiconductor device and a method of fabricating the same, and more particularly, to a semiconductor device which can prevent electrical contact failures, and a method of fabricating the same.
2. Description of the Related Art
Higher integration in semiconductor devices has resulted in a decrease in the size of a contact hole that connects one element or layer to another element or layer, while resulting in an increase in the relative thickness of an interlayer insulating layer. Thus, the aspect ratio of the contact hole increases, and an alignment margin of the contact hole decreases, in a photolithography process. As a result, forming small contact holes using conventional techniques becomes increasingly difficult with further integration of semiconductor devices.
Accordingly, the size of a buried contact (BC), which is a contact for forming a storage node, has also decreased. In this regard, several problems may be presented. For example, the size of the contact hole gradually decreases at the region of contact with the lower interconnection line, or the formation of contact holes using a photolithography process in highly integrated semiconductor devices can lead to unreliable results. In this regard, after forming the contact hole for extending the width of the buried contact (BC), extending of the contact hole can be completed by performing a wet etch process thereon.
Meanwhile, as the integration of semiconductor devices increases, the size of a bit line used in memory devices becomes further reduced, and a margin for insulating an underlying pad becomes insufficient during the wet etch process performed for the purpose of increasing the size of the buried contact, thereby increasing the likelihood of partial exposure of an adjacent pad. Accordingly, an etching solution may penetrate through a direct contact (DC) that electrically connects the bit line to an underlying contact pad, so that a conductive material can become erroneously etched. In particular, a silicide layer formed at an interface between the contact pad and the direct contact (DC) can become easily damaged by an etching solution.
Therefore, the direct contact (DC) of the underlying bit line may be partially filled with an insulating material or a conductive material of a buried contact (BC) in a subsequent process, thereby resulting in unwanted electrical contact failures in the manufacture of semiconductor devices.